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Tephrosia vogelii (Vogel's
Tephrosia) General It is a shrub 1–3(4) m high, usually much branched and bushy. Stems brown tomentose with long flexuous hairs intermixed among shorter and denser spreading hairs. Leaves with (6)8–13(15) pairs of leaflets; petiole 9–28 mm long, petiole and rachis together (9)11–22(27) cm long, tomentose like the stem; leaflets 2.5–5.5(7.5) × (0.6)0.9–1.7(2.3) cm, elliptic-oblong to oblanceolate, rounded to cuneate at the base, rounded to emarginate at the apex, slightly mucronate, the upper surface rather thinly appressed-pubescent, the lower surface densely appressed-pubescent; stipules 11–20 × 2.5–4.5 mm, narrowly triangular or sometimes markedly falcate, soon falling. Flowers in dense heads up to 10(20 in fruit) cm, or the lowermost sometimes somewhat remote; bracts up to 16 × 13 mm, broadly ovate-acuminate to suborbicular-acuminate, brown or greyish tomentose, conspicuous at bud stage but soon falling as flowers open; pedicels 14–26 mm long, brown tomentose. Calyx 14–20(24) mm long, brown or greyish tomentose; upper and lateral teeth about twice as long as the tube, oblong, ± truncate at the apex, the lower tooth about 1.5 times as long as the lateral, strongly grooved and upwardly curved distally into a keel-like shape. Petals white, rarely the standard purple; standard 24–30(34) mm long, truncate to strongly cordate at the base, the wings and keel petals somewhat shorter. Upper stamen loosely attached to, and easily detachable from, the adjacent stamens about the middle of the filament. Ovary tomentose; style pubescent. Pods 9–14.5 × 1.3–1.7 cm, light brown lanate-tomentose. Seeds numerous (more than 15), 6–8 × 4–4.5 × 2–2.5 mm, black, smooth, with a well developed white U-shaped aril c.2 mm long. Plant parts with insect-controlling properties Mode of action Target organisms Preparation and
application In experiments in Zambia, Tephrosia leaf powder admixed at a rate of 0.1% (w/w) with cowpea seeds proved highly effective in controlling the bruchid, Callosobruchus rhodesianus, which is an important pest on cowpea seeds. This treatment was more potent than the officially recommended Malathion. Germination was between 46 and 63% compared with 4.2 and 0% of Malathion. However, it is recommended to establish the safety of the treated seeds for human consumption.
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Copyright © 2010
The Natural Resources Institute, University of Greenwich